This invention relates to turbine inlet air filtration systems and, more specifically, to a filter holding frame assembly that incorporates devices for holding one or more filters in a surrounding frame.
Gas turbines used for power generation are frequently located in industrial areas close to other combustion sources where the local atmosphere can contain high levels of small particulates such as carbon. Power plants may also be located in deserts and other arid environments where high levels of particulates such as sand can also significantly impair the performance of the turbine. It is therefore essential that inlet air filtration systems be optimized to minimize negative impact on turbine performance due to particulate-laden air.
In the past, filters have been retained in their respective holding frames by various methods. For example, a lift and drop method has been used where a holding frame is comprised of horizontal channels, the top channel being deeper than the bottom channel. This allows a filter to be inserted into the top channel and then dropped into the bottom channel. The advantage of this method is simplicity and lack of clips and/or clamps. However, the sealing of the filter and its frame relies on the airflow through the filter creating a force that compresses the filter gasket. As a result, the sealing is not 100 percent effective. Moreover, due to the weight of typical V-cell filters, this method is not suitable for front panel filters. A spring clip method has also been used where four (4) spring clips are located in the respective corners of each filter to provide a more positive compression of the filter gasket. This method is more complex and costly, however, and the spring clips are not robust. Another technique employs a screw-clamp located in each corner of the filter for compressing the filter gasket. Effective compression of the gasket is achievable, but difficult to confirm. With this technique, removal and replacement of filters is a time-consuming process, due to the length of the screws employed. The screws also pose a potential health and safety risk to the extent they protrude from the holding frame. Moreover, None of the above methods are suitable for both retention and sealing of back-to-back V-cell filters in a single frame assembly.